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Vol 46, No 11 (2019)
- Year: 2019
- Articles: 9
- URL: https://journals.rcsi.science/1068-3356/issue/view/14170
Article
Generation of Terahertz Radiation in Gas Media with Variable Structure when Focusing Two-Color Femtosecond Laser Pulses
Abstract
The possibility of modulating the power of terahertz radiation generated in the laser plasma produced when focusing two-color femtosecond laser pulses in air, when using a gas jet directed to the plasma formation region, is demonstrated.
333-335
336-339
Radiation-Induced Absorption of Light in Undoped-Silica-Core Optical Fibers in the Near-Infrared Range: Effect of Drawing Conditions
Abstract
Eight identical undoped-silica-core, fluorosilicate-cladding preforms have been drawn into optical fibers under different drawing regimes (temperature T, tension, and speed). Next, the fibers have been γ-irradiated, with radiation-induced absorption (RIA) of light measured at the wavelength λ = 1.55 µm and at the dose of 2.5 kGy (7.4–7.6 Gy/s). RIA is found to strongly increase with an increase in T, which proves to be the main drawing parameter determining the fiber radiation resistance. It is established that the RIA dependence on T−1 is exponential.
340-343
Optical Properties of Plasmonic Nanoantennas Based on Arrays of Interacting V-Shaped Structures in the Mid-IR Range
Abstract
Polarization-selected IR transmission, IR reflection, and IR absorption spectra of arrays of V-shaped gold structures are experimentally studied for various structure periods. To form a local region of the enhanced electromagnetic field in subwavelength nanogaps, arrays with unit cells consisting of two V-shaped structures, facing each other by acute angles with gaps of 0, 50, 100 nm were also used. The results of comparison of spectral data with measurements of dimensional parameters using atomic-force microscopy and scanning electron microscopy are presented. The possibility of using the fabricated structures to achieve the effect of surface-enhanced IR absorption by quantum dots is shown.
344-347
Maximum Proton Trapping Energy in the Earth Radiation Belt
Abstract
During the PAMELA satellite experiment started in 2006 onboard the Resurs-DK1 spacecraft (350–600 km, an inclination of 70°), cosmic ray charged particle fluxes in low near-Earth orbits were measured to the beginning of 2016. The data obtained during the experiment on high-energy proton (0.1–10 GeV) fluxes in the radiation belt made it possible to measure maximum proton trapping energies in various solar activity phases. The measurement results showed that the maximum proton trapping energy at L shells of 1.16–1.22 in the periods of both solar activity minimum (2009) and maximum (2014) was ∼2 GeV.
348-350
Experimental Methods for Studying the Power Contrast of Laser Radiation
Abstract
The streak-camera method for measuring the laser radiation (LR) front profile with a large dynamic range and the method for measuring the power contrast based on photodiodes are described. The results of the implementation of these measurement methods at the “Luch” facility of the RFNC—VNIIEF using the SER-5 streak camera developed by the authors and specially developed optical schemes are presented. The results of measurements of the LR power contrast, performed in power experiments and demonstrating the possibility of measuring deep profiles of pulses with a dynamic range to 106 and 109 and a time resolution of 250 ps and 70 ps (at the first and second harmonics, respectively) are presented.
351-354
355-359
Ion—Plasma Beam Formation on the Plasma Focus Installation
Abstract
The method for forming and extracting a homogeneous ion—plasma beam using metal diaphragms on the Mather-type Plasma focus installation is considered. The results of the interaction of ion—plasma beams with Al, Cu metal foils and glasses are presented. It was shown that the energy flux density of the ion—plasma beam absorbed in the target reaches ∼2 · 108 W/cm2.
360-363
Destruction of Ferruginous Quartzite in Rock Mass by High-Gradient Magnetic Fields
Abstract
The results of experimental and theoretical studies of the applicability of strong pulsed magnetic fields to destruct ferruginous quartzite are presented. A “magnetokinetic” model of ferruginous quartzite destruction, based on the interaction of magnetite grains with quartz matrix at the passage of a high-gradient electromagnetic pulse through rock, is proposed. It is shown that the high-gradient pulsed magnetic field can be used to destruct quartz-containing rocks in a massif during both drilling and blasting and when solving geoenvironmental problems in mining crystalline rocks, complex-structure massifs of ferruginous quartzites by the example of deposits of the Kursk magnetic anomaly (KMA) and others.
364-370